1. Field of the Invention
The present invention relates generally to a method and apparatus for fabricating a well used for monitoring and remediation of contaminated soil and ground water. More specifically, the present invention relates to a method and apparatus for selecting a sand pack mesh for a filter pack and a well casing slot size for a well using soil classification data derived from a cone penetrometer test.
2. Description of the Prior Art
In a standard well, a bore hole is first drilled into the ground. Normally, the well water is sampled as part of a water quality monitoring program. A well casing is then inserted into the bore hole. Normally, the well casing houses a pumping mechanism or other mechanical components which comprise the operational features of the particular well.
The well casing will normally include a portion that is permeable to groundwater. The remainder of the well casing is typically impermeable to insure proper hydraulic flow of the liquids through the well casing at a specific depth intervals, as dictated by the design of the casing.
The space in between the exterior surface of the well casing and the interior surface of the bore hole is then filled with an annular fill material. This annular fill material, which operates as a filter or cleaning device, may be a permeable material, such as gravel or sand.
Water, which is pumped through the well is directed through a filter or cleaning device placed in the annular space of the well casing. Ground water so directed will capture impurities or contaminants leached or dissolved from the surrounding soils into the groundwater, thus passing impurities or contaminants from the surrounding soils to the filter or cleaning device along the screened portion of the well casing.
In the past selection of the filter (also known as the gravel pack or primary filter pack) and well casing slot size which is based on the filter pack was an extremely time consuming, expensive and difficult process requiring soil sampling, sieve analysis, and reference to standard recommendations. What is needed is a relatively simple method and apparatus by which a user can select the sand pack mesh and the well casing slot size when the soil type which is contaminated has been identified.